Jeff,
I have just added subqueries to SPIN and will send you an email off-
list with an update.
Holger
On May 28, 2009, at 1:19 PM, Schmitz, Jeffrey A wrote:
>
> Ah yes, I vaguely remember reading that now that you mention it, and
> as
> that's exactly what I'm trying to do, I'm sure that's what is
> happening.
> Sorry, too much to keep track of.
>
> Any rough idea if/when that will be added? Our implementation REALLY
> needs a way to create and use re-usable SPARQL Filter SPIN functions,
> and from what I can tell right now, the only way to implement them
> is to
> use sub-selects, unless of course the Jena folks were to implement the
> previously suggested "MATCH" assignement capability (I won't hold my
> breath on that one) :-)
>
> As an interesting side note, using a subselect with a reference to a
> SPIN function from the TBC SPARQL tab DOES work. e.g. with
> getProjectUser defined as a SPIN Function this works:
>
> SELECT ?value
> {
> {SELECT ?user
> WHERE {
> LET(?user := :getProjectUser("DEFAULT_PROJECT", "jeff"))
> }
> }
> {SELECT ?user ?value
> WHERE {
> ?user :firstName ?value
> }
> }
> }
>
> Thanks!
> Jeff
> p.s. as a very ironic side note, my ctrl key has stopped working.
> Guess
> it didn't like me disparaging ctrl-space.
>
>
>> -----Original Message-----
>> From: Holger Knublauch [mailto:[email protected]]
>> Sent: Thursday, May 28, 2009 2:32 PM
>> To: [email protected]
>> Subject: [tbc-users] Re: [SPIN] Using FILTER with function arguments
>>
>>
>> Hi Jeff,
>>
>> as posted a few weeks ago, SPIN RDF syntax does not support
>> sub- selects yet. Maybe this is what you are experiencing here?
>>
>> Holger
>>
>>
>> On May 28, 2009, at 11:14 AM, Schmitz, Jeffrey A wrote:
>>
>>>
>>> For some reason, I'm having trouble executing the
>> "sub-query" sparql
>>> query using the SPIN api. Even after simplifying the query
>> to remove
>>> the LET and the SPIN function, the query with sub-queries doesn't
>>> return results when it should.
>>>
>>> Specifically, when I execute the following query in my code
>> using the
>>> SPIN API, as well as when I execute it from the TBC SPARQL tab, it
>>> works
>>> correctly:
>>>
>>> SELECT ?value
>>> WHERE {?user a ModelManagement:User .
>>> ?user ModelManagement:firstName ?value
>>> }
>>>
>>> However, when I execute the following, I think logically equivalent
>>> query, I get no results:
>>>
>>> SELECT ?value
>>> {
>>> {SELECT ?user
>>> WHERE {
>>> ?user a ModelManagement:User .
>>> }
>>> }
>>> {SELECT ?user ?value
>>> WHERE {
>>> ?user ModelManagement:firstName ?value
>>> }
>>> }
>>> }
>>>
>>> This query does work correctly from the TBC SPARQL tab, and
>> I can also
>>> run this query in my code using just the jena/arq API and it works
>>> correctly.
>>>
>>> I've pasted below the code I use to execute the queries
>> using the SPIN
>>> API, which seems to work for most cases. I have a feeling
>> there's a
>>> more concise way to do this, but that's a topic for another post...
>>>
>>> //Create the ARQ Query from the SPARQL string.
>>> arqQuery = QueryFactory.create(sparqlStr,
>> Syntax.syntaxARQ);
>>>
>>> //Get the ARQ2SPIN utility, specifying model to
>> be queried.
>>> ARQ2SPIN a2s = new
>>> ARQ2SPIN(modelManagementInst.memModel);
>>>
>>> //Create a SPIN query from the ARQ Query
>>> org.topbraid.spin.model.Query spinQuery =
>> a2s.createQuery(arqQuery,
>>> null);
>>>
>>> //Wrap up both queries in a SPIN wrapper.
>>> QueryWrapper wrapper = null;
>>> String ruleText = null;
>>> if (spinQuery != null) {
>>> StringPrintContext p = new StringPrintContext();
>>> spinQuery.print(p);
>>> if (ruleText == null) {
>>> ruleText = p.getString();
>>> }
>>> arqQuery =
>>> ARQFactory.get().createQuery(modelManagementInst.memModel,
>>>
>>> p.getStringBuilder().toString());
>>> wrapper = new QueryWrapper(arqQuery,
>> ruleText, spinQuery,
>>> ruleText);
>>> }
>>>
>>> //Get the arq query from the wrapper
>>> arqQuery = wrapper.getQuery();
>>>
>>> //Get the query execution
>>> QueryExecution selQe =
>>> ARQFactory.get().createQueryExecution(
>>> arqQuery,
>>> modelManagementInst.memModel);
>>>
>>> //Execute it
>>> ResultSet rs = selQe.execSelect();
>>>
>>>
>>>> -----Original Message-----
>>>> From: Schmitz, Jeffrey A
>>>> Sent: Thursday, May 28, 2009 11:06 AM
>>>> To: [email protected]
>>>> Subject: [tbc-users] Re: [SPIN] Using FILTER with function
>> arguments
>>>>
>>>>
>>>> No, that's not working in this case...
>>>>
>>>> SELECT ?user ?value
>>>> WHERE {
>>>> LET(?user := :getProjectUser("DEFAULT_PROJECT", "xxx")) FILTER
>>>> (bound(?user)) ?user :firstName ?value }
>>>>
>>>> Still returns everything with a firstName property.
>>>>
>>>>> -----Original Message-----
>>>>> From: Holger Knublauch [mailto:[email protected]]
>>>>> Sent: Thursday, May 28, 2009 10:22 AM
>>>>> To: [email protected]
>>>>> Subject: [tbc-users] Re: [SPIN] Using FILTER with
>> function arguments
>>>>>
>>>>>
>>>>> Jeff,
>>>>>
>>>>> wouldn't it be sufficient to add a FILTER bound(?var) after the
>>>>> function call?
>>>>>
>>>>> Holger
>>>>>
>>>>>
>>>>> On May 28, 2009, at 7:06 AM, Schmitz, Jeffrey A wrote:
>>>>>
>>>>>>
>>>>>> "The function returns no binding and therefore ?user is
>>>> unbound and
>>>>>> will be iterating over all possible subjects of the firstName
>>>>>> triples."
>>>>>>
>>>>>> Hmmm, not what I was expecting. I guess I would have
>>>>> expected it to
>>>>>> act more like normal SPARQL variable chaining occurrs,
>>>> e.g. in the
>>>>>> following
>>>>>> query:
>>>>>>
>>>>>> SELECT ?user ?value
>>>>>> WHERE {?user a :NonExistantClass .
>>>>>> ?user :firstName ?value}
>>>>>>
>>>>>> ?user is "unbound" after the first line
>> (NonExistantClass doesn't
>>>>>> really exist), and this query returns no results instead of
>>>>> everything
>>>>>> in the model with a firstName property. Even if you reverse the
>>>>>> order:
>>>>>>
>>>>>> SELECT ?user ?value
>>>>>> WHERE {?user :firstName ?value .
>>>>>> ?user a :NonExistantClass .
>>>>>> }
>>>>>>
>>>>>> You still get no results. But change it to something like:
>>>>>>
>>>>>> SELECT ?user ?value
>>>>>> WHERE {(LET ?user := :filterOnClass(:NonExistantClass)
>>>>>> ?user :firstName ?value}
>>>>>>
>>>>>> And you do get everything in the model with a firstName property.
>>>>>>
>>>>>> Be that as it may, using subqueries I think I'm able to get the
>>>>>> behavior I'm looking for. A little verbose, but if I understand
>>>>>> things, I think you'd have to do this anytime you wanted
>> to use a
>>>>>> re-usable SPIN filtering function:
>>>>>>
>>>>>>
>>>>>> SELECT ?user ?value
>>>>>> {
>>>>>> {SELECT ?user
>>>>>> WHERE {
>>>>>> LET(?user :=
>>>>>> ModelManagement:getProjectUser("DEFAULT_PROJECT",
>>>>>> "xxx"))
>>>>>> }
>>>>>> }
>>>>>> {SELECT ?user ?value
>>>>>> WHERE {
>>>>>> ?user ModelManagement:firstName ?value
>>>>>> }
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> In the above query, if the user specified in the LET
>>>> (xxx) doesn't
>>>>>> exist, nothing is returned.
>>>>>>
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Holger Knublauch [mailto:[email protected]]
>>>>>>> Sent: Wednesday, May 27, 2009 9:38 PM
>>>>>>> To: [email protected]
>>>>>>> Subject: [tbc-users] Re: [SPIN] Using FILTER with function
>>>>> arguments
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On May 27, 2009, at 12:21 PM, Schmitz, Jeffrey A wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> It's getting curiousor and curiousor...
>>>>>>>>
>>>>>>>> Using the TBC SPARQL tab, when I call a function that filters
>>>>>>>> according to an argument, e.g.:
>>>>>>>>
>>>>>>>> SELECT ?user
>>>>>>>> WHERE {
>>>>>>>> ?project ModelManagement:hasUser ?user .
>>>>>>>> ?user Common:name ?username .
>>>>>>>> FILTER (?username = ?arg1) .
>>>>>>>> }
>>>>>>>
>>>>>>> If the function returns no binding then it will be
>>>> comparable to a
>>>>>>> wildcard in the query below.
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> As long as I pass in an argument that has a match:
>>>>>>>>
>>>>>>>> SELECT ?value
>>>>>>>> WHERE {LET(?user := ModelManagement:getProjectUser("john"))
>>>>>>>> ?user ModelManagement:firstName ?value}
>>>>>>>>
>>>>>>>> the function returns just one result as expected (in this
>>>>> case for
>>>>>>>> some reason the blank result rows aren't returned).
>>>>> However, if I
>>>>>>>> pass in a value that has NO matches:
>>>>>>>>
>>>>>>>> SELECT ?value
>>>>>>>> WHERE {LET(?user := ModelManagement:getProjectUser("xxx"))
>>>>>>>> ?user ModelManagement:firstName ?value}
>>>>>>>>
>>>>>>>>
>>>>>>>> It acts like the FILTER statement isn't there, and all
>>>>>>> User's names in
>>>>>>>> the model are returned. I would have expected no
>> results to be
>>>>>>>> returned. Btw, I'm seeing this same behavior in my code
>>>>> too. Am I
>>>>>>>> thinking about this wrong, or is there perhaps a
>>>> problem with how
>>>>>>>> FILTER works within a Function?
>>>>>>>
>>>>>>> No, the behavior is correct (as far as I understand your
>>>> example).
>>>>>>> The function returns no binding and therefore ?user is
>>>> unbound and
>>>>>>> will be iterating over all possible subjects of the firstName
>>>>>>> triples.
>>>>>>>
>>>>>>> In your first email, please keep in mind that the
>>>>> execution order of
>>>>>>> ARQ might be different from what you have typed it. In
>>>>> particular, I
>>>>>>> find often that LET statements are executed at the end,
>>>>> and therefore
>>>>>>> lead to more iterations than expected.
>>>>>>>
>>>>>>> Holger
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>
>>>>
>>>>>
>>>>
>>>
>>>>
>>
>>
>>>
>>
>
> >
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